Refrigerating system



Oct. 31, 1939. M. w. KENNEY ET Al.

REFRIGERATING SYSTEM Filed July 7, 1934 5 Sheets-Sheet l aJJ | I I I I l 4 I I I I Oct. 31, 1939.` M W KENNEY 5T AL 2,178,373

REFRIGERATNG` SYSTEM Filed July 7, 1934 3 Sheets-Sheet 2 L R M R D N OPERHTING JMW@ REFRIGERHNT K /mm/ @d Oct. 31, 1939. M w KENNEY Er AL 2,178,373

REFRIGERATING SYSTEM Filed July '7, 1934 5 Sheets-Sheet 3 Patented Oct. 31, 1939 UNITED STATE REFRIGERATING SYSTEM Mahlon W. Kenney, Chicago, land Arthur E. Constantine, River Forest, lll., assignors, by' mesne assignments, to William C. Grunow,

Chicago, Ill.

Application July '7, 1931i, Serial No. 7%,626

7 Claims.

ence to the provision of an improved evaporatorfor -use in such a system.

. An important object resides in providing apparatus of the character mentioned, comprising a refrigerant circulating system including, a lubricated compressor, a condenser and an evaporator wherein the medium utilized for, lubricating the compressor is` substantially insoluble in the refrigerating medium when in gaseous condition,'

but -is readily soluble therein when the refrigerant is in liquid condition, the system being arranged so that the refrigerant is maintained in gaseous condition while in the compressor, so that only a minimal quantity of the lubricant, such as may become entrained in the gaseous refrigerant, will be carried from the compressor.

A further object is to form the evaporator with means to continuously separate dissolved lubricant from the liquid refrigerant therein, and Withdraw the separated lubricant from the evaporator vand deliver the same to the compressor.

lAnother important object is to provide an evaporator wherein liquid refrigerant containing minimal quantities of dissolved lubricant, may be evaporated, said evaporator being formed with a lubricant ejector in position to receive liquid refrigerant containing dissolved lubricant, to separate the lubricant by evaporating the refrigerant and to deliver the separated lubricant from the evaporator by gravity action.

Another important object is to provide, in an evaporator for liquid refrigerant containing dissolved lubricant, means for continuously separating lubricant from the liquid refrigerant and removing the separated lubricant from the evaporator, said means comprising an ejector including a spoon-like receiver in position, above the liquid refrigerant level in the evaporator, to continuously collect, at a predetermined restricted rate', liquid refrigerant containing dissolved lubricant sprayed, above the liquid refrigerant level in the evaporator, as a result of the ebullition of the liquid refrigerant in the evaporator, the ejector being'arranged to evaporate the so collected refrigerant rapidly and to drain the residual lubricant from the evaporator.

A further object is to provide a lubricant ejector comprising a separator portion extending outside of the evaporator, and connected with -a refrigerant receiver located Within the evaporator, so that refrigerant and dissolved lubricant collected in the receiver may drain into the separator, 5

which being exposed to relatively high temperature outside the evaporator, causes rapid evaporation of the liquid refrigerant in the separator, and consequent separation of the refrigerant from the lubricant.

A further object is to form the separator with a plurality of pockets into which liquid, delivered from the spoon-like receiver, may successively drain in order to promote the progressive evaporation of the liquid refrigerant to the end that 15 the lubricant, when it reaches the discharge end of the separator, may be in substantially refrigerant-free condition.

Another important object of the invention is to provide a compression-evaporation refriger- 20 ating system including a lubricated compressor and an evaporator, and employing a lubricating medium which will only form a solution with the liquid refrigerant, the evaporator having improved means for extracting and delivering, to 25 the compressor, lubricant which may become dissolved with the liquid refrigerant and carried into and entrapped in the evaporator.

Another important object is to provide a refrigerating system including a lubricated compressor 30 and employing a refrigerant, such as dichloromethane, which will only form a solution with the lubricant when the refrigerant is in the liquid state, and includingan evaporator having means operating continuously to withdraw from the 35 evaporator and deliver, to the compressor, lubricant which becomes entrapped in the evaporator and which, since it will not dissolve with the evaporated refrigerating medium, cannot be carried from the evaporator by the gasied refriger- 40 ant returning to the compressor.

Another important object is to provide a refrigerating system including a refrigerant compressor and an evaporator having a lubricant extractor comprising an elevated spoon positioned to receive the lubricant' in the evaporator and means to drain lubricant from the spoon. to the compressor; afurther object being to construct the evaporator to promote violent boiling of the refrigerant in the immediate vicinity of the spoon the lubricant extracting tube with a spoon con- 7,0, tion of the lubricant ejector with openings imnecting with the tube through a restricted opening or throat to control the rate at which the liquid may flow from the spoon to the extracting tube; a further object being to construct the spoon to receive a limited quantity-of liquid only, said spoon having perforations through which liquid in excess of the capacity of the spoon may drop back into the refrigerant in the evaporator; a still further object being to form the extracting tube inwardly of the restricted throat with a narrow gangway defined on either side by openings communicating with the interior of the evaporator and across which gangway a limited amount of the liquid received through the throat may pass between said openings and reach the interior of the tube, the liquid passing on the gangway being retained thereon by the surface tension of the liquid and the balance of the liquid received through the throat being returned to the evaporator through the openings defining the gangway, whereby a limited portion only of the liquid received on the spoon is delivered into the extractor tube, and thence removed from the evaporator.

Another important object is to provide, in combination with an evaporator for liquid refrigerant containing dissolved lubricant, a refrigerant separator and ejector comprising a spoon-shaped receiver extending above the liquid refrigerant level within the evaporator in position to collect liquid refrigerant containing dissolved lubricant A further object is to form the spoon-like receiver portion of the lubricant ejector as a sheet metal stamping having upturned peripheral edges and a plurality of' perforations, defined by upwardly embossed edges, within the upturned peripheral edges of the stamping whereby the receiver is adapted to collect a limited portion of the liquid refrigerant spray falling within the peripheral edges of the stamping as a result of the boiling of the liquid refrigerant in the evaporator, the remainder of the liquid spray returning to the body of refrigerant in the evaporator through said perforations.

A further object is to form the lubricant ejector witha restricted orice or throat, between the spoon-like receiver and the portions of the ejector wherein separation of the lubricant and refrigerant occurs, so that liquid collected in the receiver is required to pass through said throat in entering the separator, a further object being to form said throat as an elongated opening of restricted width, whereby the liquid entering the separator is in substantially film-like form.

A further object is to form the separator pormediately within the restricted throat through which the liquid enters from the spoon-like receiver, said openings affording means whereby gaseous refrigerant, evolved as a result of evaparrears oration in the separator may re-ent'er the evaporator.

A further object is to form said openings on the lower side of the separator in position to define, between at least two such openings, a restricted pathway across which the liquid entering the separator is required to flow so that only that portion of the liquid maintained on said restricted pathway by surface tension may pass through the separator, the remainder of the liquid draining through said openings and falling into the liquid refrigerant body in the evaporator.

A further object is' to form the lubricant ejector as a tube of heat conducting material, the lower side of which is formed-with a series of corrugations, affording internal pockets, into and through which the liquid may progressively cascade in passing through the separator.

Another important object is to provide a refrigerant evaporator comprising a pair of sheets of heat conducting material embossed to provide a pair of spaced apart headers and a plurality of refrigerant ducts interconnecting the head-L ers, at least one of said sheets being formed with a refrigerant inlet communicating with certain of said ducts below one of said headers, and at least one of said sheets having gaseous refrigerant outlet means formed in at least one of said headers and opening above the liquid refrigerant level therein.

A further object is to form at least one of said headers with a gaseous refrigerant outlet and another header with a lubricant ejecting connection.

Another object is to interconnect the headers by means of a conduit opening at its opposite ends above the liquid refrigerant level in said headers.

Another important object is to provide a refrigerant evaporator comprising a pair of sheets of heat-conducting material, wherein at least one of which is embossed to provide spaced apart header forming depressions at the opposite ends of the sheet, and wherein at least one of said sheets is embossed to provide a plurality of spaced apart, preferably parallel, refrigerant ducts, whereby, when said sheets are secured together, said ducts will communicate at their opposite ends with said spaced headers.

Another object is to provide an evaporator comprising means forming a pair of chambers interconnected by conduits and adapted to contain a boilingv liquid refrigerant and a lubricant drain comprising a tube having a spatulate end extending into one of said chambers above the liquid refrigerant level therein, and in position to receive lubricant trapped in the evaporator upon the spatulate end of the tube by spattering due to the'boiling of the refrigerant.

A further object of the invention is to form the evaporator, in an inexpensive manner, by fastening together a pair of interfitting plates having depressed portions-forming refrigerant headers and ducts between the plates, when fitted together, 'a lubricant drain tube extending through and secured in place, as by brazing, in an opening formed in one of the interfitting plates opposite one of the headers.

A further object is to emboss at least one of the evaporator forming sheets with a groove or grooves interconnecting said ducts intermediate the headers, and to form said grooves in position such that when the evaporator forming sheets are bent to form spaced apart walls containing the headers, said grooves will provide registering inwardly extending beads on the facing surfaces of said spaced Walls and adapted to provide means for supporting objects to be cooled between said spaced walls.

A further object is to provide one of the bead forming grooves with a refrigerant inlet connection.

Another Objectis to arrange the refrigerant inlet as a pipe extending within one of said grooves, and having one end adapted for connection with a liquid refrigerant supply, and the other end opening in one of said ducts immediately beneath the lubricant ejector, so that relatively cold vliquid refrigerant entering the duct through said pipe will promote violent boiling in the duct immediately below the lubricant ejector in order to deposit liquid refrigerant containing dissolved lubricant in the spoon-shaped receiving portion of the ejector by spattering.

Another important object of the invention is to utilize the forces liberated by the boiling of the refrigerant in the evaporator to assist in the removal of dissolved lubricant held in the evaporator in solution in the liquid refrigerant therein.

Another important object of the invention resides in forming an evaporator by embossing grooves and depressions in at least one of a pair of cooperating plates of heat conducting material, securing the embossed plate together as by welding around the peripheral edges and between the grooves and depressions to provide an evaporatorI comprising a pair of spaced apart refrigerant headers and a plurality of refrigerant ducts communicating at their opposite ends with said headers, and finally forming said plates, after welding to provide a pair of spaced apart side Walls and an interconnecting wall whereby to form a receptacle for the reception of objects to be cooled between said side walls.

A further important object of the invention is to form the outer of said evaporator forming pair v of plates with the grooves which connect with the header portion while forming the inner plate with channels intersecting and communicating with said grooves, whereby at least one oi' said channels may comprise an inlet refrigerant header in the finished unit.

Another important object resides in providing a float controlled expansion valve in a refrigerating system of the character mentioned, said valve being positioned to receive liquid refrigerant under pressure from the condenser, and being adapted-to maintain a quantity of the liquid refrigerant therein While delivering liquid refrigerant to the evaporator as needed to maintain a desirous liquid refrigerant level in the evaporator.

A further object is to form the float controlled expansion valve of formed sheet metal parts, and further to connect the valve with the condenser through a refrigerant strainer.

Another object is to form the valve with an air and fluid tight inlet through which the refrigerating medium may be introduced into the system, and through which any air entrapped in the refrigerant system may be expelled.

Another important object is to provide a mechanical refrigerating system, including a cooling device, and power operated means for delivering refrigerating energy for liberation at the cooling device, said power operated means including devices for liberating heat during the operation of the system anda uid-circulating element for directing a stream of cooling fluid to said heat-liberating devices for the purpose of means is mounted on a common support for insertion as a unit in a housing including walls or partitions arranged in position to cooperate with the fluid circulating element in order to dlrect the cooling fluid stream, created by the operation of said element, to said heat liberating devices; a further object being to form the housing as a part of a domestic refrigerator cabinet in which the cooling device is also mounted.

Another important object is to provide a mechanical refrgerating system including a cooling device, and power operated means for delivering refrigerating energy for liberation at the cooling device, said power operated means including a device liberating heat during the operation of the system, a motor driven device and air circulating means for cooling the heat liberating and motor driven devices wherein electrical means including al pair of condenser motors is provided with one motor drivingly connected with the air circulating means and the other connected for driving the motor driven device and wherein said electrical means include electrical connections for starting and operating the condenser motors from an 'external source of electrical power; a further object being to arrange said electrical connections for thermostatic control of said motors in response to temperatures prevailing in the vicinity of the cooling device.

These and numerous other objects and inherent advantages and functions of the invention will be apparent as the invention is more fully understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of our invention.

Referring to the drawings:

Figure 1 is a perspective view of refrigerating apparatus embodying our present invention as assembled in a cabinet to form a domestic refrigerator;

Figure 2 is a sectional view in horizontal section taken through the device shown in AFigure 1;

Figure 3 is a diagrammatic sketch showing electrical connections forming a system for powering and controlling the operation of the refrigerating apparatus shown in Figure l;

Figure 4 is a top plan view, partially in section, of a refrigerant evaporator forming a part of the apparatus shown in Figure 1;

Figures 5 and 6 are respectively an end and a side view of the evaporator shown in Figure 4;

Figures 7, 8 and 9 are sectional views taken substantially along the lines 'l-1, 8-8, and 9 9, respectively, in Figures 6, 7 and 8;

Figure 10 is a sectional View taken substantially along the line llll0 in Figures 5 and 6; and

Figure 11 is a sectional view through afloat controlled expansion valve forming a part of the apparatus shown in Figure 1.

To illustrate our invention, we have shown in the drawings a refrigerating system comprising refrigerating medium may be liquefied as by cooling. The liq'uid refrigerant may be delivered from the condenser to the evaporator, preferably through an expansion device comprising, in the illustrated embodiment, a float controlled valve l'i. .The liquid refrigerant thus delivered in the evaporator at relatively low pressure 'boils and changes its state from liquid to gaseous condition with consequent absorption of heat at the evaporator. The gaseous refrigerant thus evolved in the evaporator may be returned to the compressor for a repetition of the cycle. We find that it is desirable, though by no means essential, to connect a dehydrator it, of any suitable or preferred character, in the circulating system preferably between the condenser and the iioat controlled valve lil for the purpose of removing, from the liquid refrigerant, any traces of moisture conside walls and an integral top, and a sheet metal cover portion i8 of generally semi-spherical configuration sealed to the lower opening of the cylindrical member i6 in order to form a sealed housing providing a float chamber, the cupshaped member i8 having peripheral flanges 22 sealed to the edges of the open ends of the shell I6. At its upper end, the shell carries an inlet fitting comprising a nipple 26 sealed in an open- Y ing formed in the shell, the inner end of the4 nipple opening into the shell and carrying a filter element 26 preferably in the form of a wire screen. The outer end of the nipple 2li is threaded for connection with the conduit leading from the condenser, so that condensed liquid refrigerants may be delivered through the nipple and screen into the oat chamber. The cupshaped portion I8 is shaped to receive a preferably spherical float member 28 carrying a valve stem 32' in position to enter a channeled sleeve 34 which is sealed at one end in an. opening located centrally in the bottom of the cup-shaped element i8, said element i8 having a strengthening ridge embossed therein around said opening. The channelled sleeve 34 provides a valve seat with which the valve stem 32 cooperates to provide a control for the liquid refrigerant delivered from the float chamber through the channelled sleeve 34. The outer end of the sleeve 34 is provided for connecting with the conduit leading to the evaporator inlet. The cup-shaped portion itl is also embossed outwardly as at Sil to facilitate the connection of supporting legs i112 by which the casing forming the float chamber may be supported in. operative position. As the level of liquid rises in the float chamber, the float 23 will be raised andwill lift the Valve stem in the sleeve 34 to permit liquid refrigerant to escape from the oat chamber to the evaporator. The walls of the casing i6 are provided with an annular in- Wardly extending groove to interttingly receive and sup-port a corresponding groove annular element 46 located within the float chamber in position to engage and limit the upward movement of the float 28 therein, and thus prevent the possibility of the lioat rising to a height in the chamber permitting the valve stem 32 `to escape from the sleeve 3d. We also iind it convenient to provide'the lvalve chamber with means permitting the introduction of the refrigerating medium into the system at this point. To this end the upper portions of the casing! t are formed with a channeled fitting i8 sealed in an opening in the casing with its channel opening at one end into the andere oat chamber. The fitting 48 outwardly of the float chamber is externally threaded to receive a cap 54 for sealing the outer end of the channel. The outer end of the channel is internally threaded to receive a valve 56, and the channel is formed with a valve seat inwardly of the threaded portion adapted to be hermetically closed by screwing the valve iii-firmly against the seat. The valve 5t is provided with a channel which, when the valve 56 is raised from its seat, provides communication between the outer and inner ends of the fitting, but which is so arranged that communication between the outer and inner ends of the tting is cut oif when the valve is firmly seated. The system may be loaded with the refrigerating medium by removing the cap 54 and valve element 56 entirely from the tting 48. A refrigerant delivery line is then connected to the fitting d8 as by threading it upon the threads which ultimately carry the closurecap 54. A desired amount of refrigerant is then pumped into the system under pressure, the compressor being operated during the loading process in order to distribute the refrigerant properly in the system. After loading is completed, the refrigerant delivery connection is broken, the valve element 56 is inserted, but is not immediately seated. A vacuum connection is then applied as by threading the same'upon the threads normally carrying the cover cap 54. This vacuum connection preferably has means manually operable without re-` moving the connection in order to seat the valve. The vacuum connection is maintained for a sulficient interval to withdraw from the system all air and moisture which has entered during the loading operation, the compressor during this air and moisture evacuation process, being preferably blanketed so that the system operates at a higher temperature than would otherwise be the case, thus driving on any air and moisture which may be dissolved or occluded in the lubricant and refrigerant. Since the lubricant is in liquid condition when'it reaches the float chamber, air and moisture will be drawn olf through the fitting 48 and the vacuum connection without abstracting any material quantity of the refrigerant.

Although the present invention is not necessarily restricted to a system embodied in domestic refrigeration, we have shown a refrigerating system arranged in a cabinet 50 of any suitable or preferred construction affording a refrigerating compartment 58, in which the evaporator or heat absorber I5 is located. The compartment 58 preferably has heat insulating walls, and includes a frontal opening giving access to the compartment, a door or other closure member 60 being provided for said opening. The motor compressor unit, the condenser, and condenser cooling means, and auxiliary apparatus for operating and controlling the same, need not necessarily be housed in the cabinet at all, but may be separately enclosed or located remotely from the cabinet, if desired. We prefer, however, to provide the cabinet with a mechanism compartment 62 adjacent and preferably immediately beneath the reirigerating compartment, and to house therein the compressor, condenser, and associated operating and control mechanism. The compressor, condenser, and associated operating and control mechanism which is enclosed in the mechanism housing, are preferably all mounted on a common panel S4 adapted for removable insertion in the cabinet so that the devices mounted on the panel may be assembled as a unit in the mechanism compartment. The mechanism compartment also is preferably formed with a partition Sii-defining chambers S and 12 on opposite sides of the partition, and within the walls of the mechanism compartment. The apparatus carried by the support 64 when the same is assembled in the mechanism compartment, is located within the chamber12 with the condenser I3 disposed in an opening 14 formed in the partition. The charnber 6E has an opening 16 through which air, blown into the chamber through the condenser and the opening 14 by the blower 21, may escape from the cabinet. The opening 16 is preferably in the bottom wall of the chamber 58, and the .mechanism compartment has an opening, preferably in the rear wall of the cabinet through which air may be drawn into the chamber 12, and around the 'compressor and expelled thence through the condenser and the opening 1li. The apparatus carried on the panel 64 may be introduced in the mechanism compartment through said rear wall opening.

The compressor may be of any suitable or convenient form, although we prefer to utilize a compressor powered by means of an electric motor 25, the motor and compressor parts being enclosed in an hermetic casing to form a sealed unit having a refrigerant inlet connected by means of the conduit 2| with the evaporator and a compressed refrigerant outlet connected with the condenser, a suitable medium for lubricating the operating parts of the motor compressor unit being-contained within the sealed casing of the unit.

The condenser 4I3 also may be of any suitable or preferred construction, preferably comprising a series of pipe coils formed with heat dissipating rins and arranged in a casing through which a cooling medium may be circulated past the pipe coils and fins for the purpose of absorbing heat from the condenser and the refrigerating medium passing therethrough. We prefer also to provide a suitable blower, preferably a fan, powered by an electric motor 21 by means of which air or other -cooling fluid may be forced through the condenser for the purpose of cooling the same.

As heretofore mentioned, the refrigeration system of our present invention is particularly well adapted for use in domestic refrigerators, for which reason we prefer to provide means for operating the compressor driving and condenser cooling motor from a single phase alternating current electrical power source, since power of this character is most usually available for the operation of domestic refrigerators. It is obvious, however, that the compressor driving and condenser cooling means may be of any suitable or preferred construction, but we prefer to utilize electric motors which may be operated and controlled simultaneously from a common power source through a common control system, in order thus `to avoid duplication of motor control elements. To accomplish the foregoing, we have shown on the drawings in Figure 3 a control systern for operating electric'motors 25 and 21 in parallel from a vcommon power source. Each motor comprises a plurality of like windings 29 and 3| connected in parallel, the windings 23 being connected to receive alternating current electrical power from the power source without substantial change in phase while the windings 3| receive power from the source through a phase changer whereby each motor may operate as a polyphase machine. The windings of each motor Aare connected together at one end and to a common conductor 33. The opposite ends of the windings i 9 of each motor are also connected together and to a common conductor 35, and

the free ends of the windings 3| are connected together and to a common conductor 31. The common conductor 33 is connected to a terminal 39 located within a casing 4| which houses a part of the electrical supply and control system. The terminal 39 is connected'by means of a conductor 42, preferably forming a part of a cable i3 which extends from the casing 4| to a thermostat control casing 45 located adjacent the evaporator. The opposite ends of the cable 43 may be provided with detachable plug connectors 41 and 49 to facilitate the electrical connections necessary between the electrical elements in the casings 4l and 45. The conductor 42 when the system is assembled for operation, forms a connection with one side of a switch 5|, preferably located in a casing 55, which switch is opened and closed by thermostatic means 52 including the thermostat element 53, which extends in heat exchange relationship with the atmosphere adjacent the evaporator i5, so that the switch 5i may be operated in response to temperature conditions prevailing in the Vicinity of the evaporator. The thermostatic means 52 also includes mechanism manually adjustable as by means of the control knob 55 which is preferably mounted on the casing 45 in order to determine the temperature prevailing in the vicinity of the evaporator at which the switch 5| will open or close. The switch 5| is in series with a man` ually operable switch 51, which also is or may be mounted on the casing 45, and which is connected by means of a conductor 59, preferably forming a part of the cable 43 to a terminal 6| in the casing 4i. The terminal 6| is connected by means of a conductor, preferably forming a part of the cable 53, with means 55, preferably in the form of an electric plug of ordinary construction, adapted for removable insertion in a power outlet socket such as is usually provided in commercial or domestic power systems. The cable 63 has another conductor adapted for detachable connection inthe external power delivery circuit which conductor connects with a terminal 61 within the casing 4|. This terminal 61 is in turn electrically connected'with one end of a solenoid 69, also located within the casing 4|, the other end of which solenoid is connected with a terminal 1| within the casing 4|. The terminal 1| is also connected with the common conductor 35 When the device 65 is connected in an external circuit, power will be delivered between the terminals 6| and 61 to energize a circuit extending between said terminals and including in series the solenoid 69, the conductor 35, the windings 29 of the motors 21 and 25, the common conductor 33, the conductor 42, the switches y5| and 51 and the conductor 59. This circuit, the switches 5| and 51 being closed, will deliver electrical power to the windings 29 of both -motors which power will be substantially in phase with the power source.

The terminal E1 is also connected bymeans of a conductor 13 with one end of an induction coil 15, the other end of which is also connected through a condenser 11 with the conductor 13, the conductor induction coil and condenser being all housed within the casing 4|. The induction coil has taps connected to stationary contacts 19 and 8| between which a shiftable blade 83 is movable in response to the current flowing through the solenoid 69. The blade S3 is electrically connected with the common concludes the several windings of the motors.

ductor 31, and is adapted to selectively connect the contacts 19 and 8| with said common conductor, and thence to the windings 3| of the motors in response to varying current flow in the solenoid 69. It will thus be seen that the motor windings 3| are included in a circuit extending from the terminal 61 through the conductor 13, the condenser-induction coil system 15-11, one or other of the contacts 19, 8|, the conductor 31, the windings 3|, and thence through the conductors 33 and 4|, the switches 5| and 51, and the conductor 59 to the terminal 6|. The reactive system comprising the induction coil 15 and condenser 11 is adapted to shift the phase of the power applied to the windings 3|, so that these windings when so energized form with the windings 29, polyphase motor driving means.

The blade 83 is adapted to vary the yreactive effect of the network comprising the induction coil 15 and the condenser 11. The motorsA preferably employed are of the so-called capacitor induction motors, the windings comprising splitphase windings adapted to be energized so that the vmotors may be started in operation from standstill position when energized with single phase alternating current applied between the terminals 9| and 61. It will be noted that both of the parallel circuits including the windings 29 and 3| are controlled by the switches 5l and 51, so that when the plug 65 is connected to a power outlet, the motors will remain inactive until both of the switches 5| and 51 have been closed. The switch 51 being manually operable, aiords manual control for the motor while the switch 5| provides for automatic control, so that the motors and hence the reirigerating system, may be placed in'operation automatically whenever the temperature in the vicinity of the evaporator rises above a predetermined value, which value may be determined by means of the knob 55. When the plug 65 is connected with an external power source, alternating current will be delivered through the parallel circuits heretofore mentioned, which in- The current delivered to the windings 29, however, Will have a different phase relationship with respect to that delivered to the windings 3| because of the reactive effect provided by the induction coil 15 and the condenser 11. In this way a rotating eld may be created in the motors for the purpose of starting the same. At the instant of starting, the switch B3 will engage one or other of the contacts 19, 8| in order that the proper phase relationship to start the motors will prevail in the current delivered to the windings. As the motors reach normal operating. speed, the current flowing in the coils 69 will decrease, and the switch 83 will be moved under the linfluence of the solenoid, and will engage the other of said contacts 19, 8|, in order to alter the reactive eiect produced upon the current flowing to the motor windings 3|, and thus to provide a desired phase relationship of current flowing in the windings for` maximum operating efciency after the motors have reached normal operating speed.

The electrical system also includes a circuit`85 containing a lamp 81, and a switch 89, said circuit being connected between the conductor 59 of the cable 43, and another conductor 9| forming a part of said cable, and connected to the terminal B1, so that whenever the plug 5 5 is connected to the external power source, the lamp 31 will be energized providing the switch 85 iS closed. The lamp 81 is or may be arranged in any suitable or convenient position Within the refrigerator compartment, while the switch 89 is arranged to cooperate with the door giving access to the compartment. The door, when closed, is arranged to hold the switch 89 in open position, the switch closing to energize the lamp and illuminating the interior of the refrigerator compartment whenever the door is opened.

As heretofore mentioned, the motor-compressor unit, the condenser, condenser cooling motor, the iloat valve, the dehydrator, and the mechanism contained in the housing 4|, are mounted on the panel 54 for assembly as a unit in the mechanism compartment, while the evaporator and the control mechanism, supported in and by the casing 45, which is mounted on the evaporator, may be assembled as a unit in the refrigerating compartment 59. The cable 43 and the refrigerant conduit 2| and 23 are preferably built into the insulated walls of the cabinet in position to facilitate the necessary connections with the evaporator and the apparatus within the mechanism compartment after the same have been assembled in the cabinet. This arrangement greatly simplifies the assembly of the refrigerating system in the cabinet, and thus reduces manufacturing costs.

The evaporator also is of simple and inexpensive construction, being preferably formed of sheets 91 and 99 of heat conducting material. These sheets are formed in such a way, that when tted and secured together, passages in which the refrigerant may be evaporated are formed between the sheets. To this end the sheet 91 is formed with spaced header forming depressions |9| and |92 near the opposite end edges of the sheet, and one of the sheets is provided with a series of parallel duct forming grooves |93 so that when the sheets arefastened together, the depressions and grooves form spaced header chambers and ||2 interconnected by a plurality of parallel ducts |94. The depressions |9| and |92 and the grooves |93 are preferably formed in the sheet 91 and the other sheet 99 is assembled in position to overlie the depressions |9| and grooves |93, the sheets being secured together as by curling the edge of one sheet about the edge of the other, as shown at |95, and by welding around the peripheral edges of the sheets and between the grooves |93 to formL a closed refrigerant space deiined, between the plates, by the header forming depressions and interconnecting-grooves. The sheet 99, also, is preferably formed with depressions |91 and |09 in position respectively opposite the depressions |9| and |92, so that the depressions |9| and |92 cooperate, in the evaporator unit, respectively, with the depressions |91 and |99 to form the elongated cylindrical header chambers and ||2. One of the sheets, preferably the sheet 99, is also formed at intervals with depressions or grooves ||3, forming ducts ||4 intersecting and communicating with the ducts |94. After the formed sheets 91 and 99 have been secured together in substantially flat condition, they may be bent to provide a channel-shaped evaporator element having a cross-sectional configuration substantially as shown in Figure 5 oi the drawings, and comprising spaced apart side walls ||5 and a bottom wall H1, the side walls containing the header chambers. with the refrigerant ducts |94 extending beneath the header spaces in the side walls H5 and in the bottom wall H1. The ridges H3 project inwardly of the facing surfaces of the walls t5, and form pairs of registering ridges on and between which objects to be cooled may be supported. In Figure 5 of the drawings we have indicated in dotted lines an object comprising a tray H9, adapted to contain liquid to be refrigerated, mounted between the walls ||5 and supported on a shelf |2|, the opposite edges of which rest upon and are supported by a pair of the ridges ||3. The shelves |2| may have downwardly extending lugs |22 struck from the material thereof and curved to fit' the ridges i|3 whereby the shelves may have slidable interfitting engagement with the ridges ||3. The opposite ends of the sheets 91 and 99 form the upper edges of the spaced walls I5 of the evaporator unit and may be bent to form flanges |23, which may be perforated as at |25 to receive supports by which the evaporator is hung or otherwise mounted Within the refrigerating chamber 58.

The evaporator also is provided with an inlet connection for liquid refrigerant which is preferably positioned to deliver the refrigerant to the evaporator at a point below the header chambers. To this end we utilize one of the shelfsupporting ridges ||3 toA form an inlet header. The ridge, so employed as an inlet header, is provided with an opening |25 at one end, and a fitting |21 having a channel |29 is secured to the evaporator with one end of the channel in communication with the header duct ||4 defined by said ridge. The fitting is provided with preferably threaded means |3| whereby the channel |29 may be connected with the conduit 23 through which liquid refrigerant is delivered from the compressor, condenser and float valve. The fitting |21 is, of course, firmly sealed on the evaporator to prevent vthe escape of the refrigerating medium from the system at the point of entry, and we prefer to provide a pipe |33 extending within the inlet header duct ||4 with one end of the pipe in communication with the channel |29 of the inlet fitting. The other end of the pipe |33 opens in the duct |4 opposite one of the refrigerant ducts |04 located substantially midway of the opposite ends of the evaporator, so that the, refrigerant will enter the evaporator at said centrally located duct. We prefer to position the inlet tting at the end of the evaporator opposite the end at which the containers ||9 are introduced into and removed from the shelves |2|, it being understood that the evaporator is mounted in the refrigerating compartment with one end facing the door to facilitate insertion and removal of objects through said door facing end. `The inlet fitting also is preferably located entirely within the lateral confines of the evaporatorwalls in order to eliminate lateral projections.

The evaporator is also provided with an outlet for evaporated refrigerant which outlet is also' located within the lateral confinesof the evaporator walls and which preferably comprises a fitting |35 secured in an opening formed preferably in the sheet 99 at the header space lll. The fitting |35 has an extension comprising a pipe or conduit |31 extending within the chamber and having an end opening above the normal liquid refrigerant level therein. The pipe |31 communicates with `a channel in the fitting 935, and the fitting is formed with a preferably threaded portion |39 by means of which the channel may be connected with the refrigerant conduit 2| leading to thesuction side of the compressor.. The outlet fitting |35 may, of course, be connected in either or both of the headers, but we prefer to connect it inthe header forming portion |01, and to interconnect the header chambers by means of a conduit I 4| fastened to and between the header forming portions |01 and |09, v

whereby gasified refrigerant collecting in the header chamber l l2 may escape through the conduit |4| into the header and thence, through the outlet fitting, to the compressor. The connecting conduit |4| in addition to its gasifled refrigerant conducting function, increases the strength and rigidity of the evaporator byassisting in holding the spaced walls H5 rigidly in spaced relationship. The conduit |4| also provides a convenient handle for carrying the evaporator unit and holding the same in position while it is being assembled in thecabinet.

When the evaporator is in operation in a refrigerating system, the level of the liquid refrigerant in the evaporator is normally maintained at an elevation in the headers as shown in Figure 5 of the drawings, the outlet pipe |31 opening above said level. The refrigerating medium which we prefer to use in the system, comprises dichloromethane, and we prefer to operate the system under pressure conditions such that the liquid 'refrigerant entering the evaporator will boil at the temperature prevailing in the vicinity of the evaporator, that is to say, within the refrigerating compartment. We prefer also to use a mineral oil for lubricating the'compressor. This oil is insoluble in gaseous dichloromethane, but is soluble in the refrigerant when liquid. Even though lubricant is not soluble in dichloromethane when in gaseous condition, slight traces of the lubricant may escape from the compressor by entrainment v with the compressed gaseous refrigerant discharged to the condenser. The gaseous refrigerant fiiquefies in passing through the condenser, and the entrained lubricant will then dissolve in the refrigerant, and we have found in operation that the liquid refrigerant delivered from the condenser contains appreciable traces of dissolved lubricant which is carried in solution with the refrigerant into the evaporator. The lubricant does not, of course, evaporate at temperatures prevailing-at the evaporator, and since dichloromethane and other refrigerants, which may be utilized in systems embodying our invention, have the capacity of dissolving lubricant in any proportion, it will be apparent that, if no means is provided for extracting the dissolved lubricant from the evaporator, the lubricant in the system will eventually become concentrated in the evaporator and thus not only impair the lubrication of the compressor but also impair the efliciency of the evaporator. We consequently provide a lubricant separator and eX- tractor which, in the illustrated embodiment,l is formed as an integral part of the evaporator.

The lubricant separator and extractor comprises a tubular element |43 communicating at one end with the outlet fitting |35 and fastened at its other end, at a slightly higher elevation, in a wall defining one of the header chambers. The element |43 is preferably connected with the header forming wall 03, so that the lubricant extractor communicates with the header chamber ||2 above the liquid refrigerant level therein, while the gasfed refrigerant outlet pipe |31 communicates with the other header chamber l. The end of the pipe |43 which is connected to the header is provided with a refrigerant collector |05, which is supported in the header immediately above the duct |03, in which the refrigerant inlet pipe |33 opens. The relatively cold liquid refrigerantentering the duct, at the open end of the inletpipe |33, sets up a vigorous boiling of the refrigerant in said duct. The vigorous boiling so initiated causes a certain amount of refrigerant, containing dissolved oil, to spatter above the refrigerant level in the header, and some of this spattered refrigerant drops into collector |65, from whence it drains into the tube Mt. The lower surface of the tube M3 is provided with a plurality of corrugations i4?, and since the tube is inclined downwardly toward the outlet fitting |35, the liquid refrigerant and dissolved lubricant will cascade progressively into the pockets provided in the tube by the corrugations Ml. Since the corrugated portion of the tube extends outwardly of the evaporator, it is subjected to the relatively higher temperature of the surrounding atmosphere, and consequently, the refrigerant is rapidly evaporated in the tube and returns into .the header through openings |49 formed in the tube, while the residual lubricant drains into the outlet fitting and is returned to the compressor through the conduit Z The separated lubricant during its travel through the conduit 2| does go into solution with the gaseous refrigerant which is also returned to the compressor through said conduit, but the lubricant maintains its separate identity as such. Theelement |45 is preferably formed as a separate sheet metal stamping having a spatulate fluid receiving portion |5I, and a fluid delivery portion |53 which is connected to the tube |43 and by which fluid,`received vin the receiving portion, is delivered into the tube. The lower portion of the inner end of the tube |43 is cut away as shown at |54 to receive the element |45. The spatulate portion of the element |45 has edges formed with an upstanding peripheral flange |55, and is also formed with perforations l51, the edges of which are embossed upwardly as at |59. The delivery portion |53 of the element |45 comprises an extension formed at one end of the spatulate portion |5|, said extension having lateral notches defining the openings |49 and a restricted neck |6| between the lateral notches, the side edges of the extension |53 being fastened to the opposite sides of the tubev |43 at the cut-out edges of the same. extension i153 opposite from the spatulate portion |5| is bent downwardly to form a lip |63 having a circular edge conforming with and secured to the tube at the end of the cut-out portion. The inner end of the tube |43, above the element |45, is closed by means of` a semi-circular disk |65. The upper curved edgeof the disk ts within and is secured to the upper end edge of the tube |43. The lower edge of the disk is cut to form a restricted opening or throat |61 through which the liquid delivered from the portion |5| passes into the tube |43. The perforations |51 in the spatulate portion |5| permit a portion of the refrigerant spray falling within the flanges |55 to return to the refrigerant body within the evaporator, so that only a part of the liquid sprayed into the spatulate receiver will drain through the throat |611. The liquid passing through the throat H51, in order to enter the corrugated portion of the tube |43 must also pass across the neck I6 i, so that only so much of the liquid as is retained by surface tension on the neck is delivered into the corrugated portion of the tube M3. The liquid not so retained upon the restricted neck |6| returns to the main body to lubricant in the headers through the openings i145.

It will be seen that the openings |51 and the restricted neck iE'l both serve to limit the amount of liquid passing into the separator tube |43 from the evaporator, and that the throat ll, by caus- The end of their aivaeve ing the liquid'to flow onto the delivery portion |53 as a film of uniform thickness and width, assists the neck Mii to perform its flow restricting function. It is desirable to thus restrict the quantity of liquid delivered to the tube |43 in order not to sacrifice the refrigerating energy. By properly proportioning the size of the apertures |51 and the width of the neck Mii, we permit only enough liquid to be delivered in the separator tube |413 as is necessary to eject lubricant from the evaporator as fast as it is introduced at the inlet.

1t is thought that the invention and its numerous attendant functions and advantages will be understood from the foregoing description; and it is obvious that numerous changes may be madein the form, construction and arrangement of the several parts of the illustrated apparatus without departing from the spirit and scope of the invention, and without sacrificing any of its attendant advantages, the embodiment herein shown being merely a preferred arrangement for the purpose of illustrating our inventive concept.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An evaporator or boiler comprising means forming an evaporator space adapted to contain an evaporable liquid at a predetermined level therein, means to exhaust, from the evaporator, gases evolved as a result of the evaporation of liquid in the evaporator, means for extracting a non-evaporable constituent of the liquid in the evaporator comprising a receiver element within the evaporator in position above the liquid level therein, to receive liquid containing the unevaporable constituent by spattering as a result of the ebullition of the evaporable constituent of the liquid in the evaporator, and means forming a drain for removing liquid in the receiver from the evaporator, said receiver being formed with a narrowed portion across which the liquid therein drains from the evaporator so that only so much of the liquid as may be retained on the narrowed portion by surface tension escapes from the evaporator.

2. An evaporator or boiler comprising means forming an evaporator space adapted to contain `an evaporable liquid at a predetermined level therein, means to exhaust, from the evaporator, gases evolved as a result of the evaporation of liquid in the evaporator, means for extracting a non-evaporable constituent of the liquid in the evaporator comprising a receiver element with- `in the evaporator in position above the liquid level therein, to receive liquid containing the unevaporable constituent by spattering as a result of the ebullition of the evaporable constituent of the liquid in the evaporator, and means forming a drain for removing liquid in the receiver from the evaporator, said drain comprising a conduit comprising a series of pockets into which the liquid delivered therein may successively flow, said conduit extending out of the evaporator and communicating with the interior of the evaporator in position to receive liquid from the receiver, whereby the evaporable constituent of liquid received in the pockets of the conduit may be rapidly evaporated due to the relatively higher ternperature of the conduit means outside of the evaporator and returned to the evaporator above the liquid level therein, while the non-evaporable constituent is removed from the evaporator through said drain. l

3. An evaporator or boiler comprising means forming an evaporator space adapted to contain an evaporable liquid at a predetermined level evaporable liquid therein to a predetermined level therein,means to exhaust, from the evaporator, gases evolved as a result of the evaporation of liquid in the evaporator, means for extracting a non-evaporable constituent of the liquid in the evaporator comprising a receiver element within the evaporator in position above the liquid level therein, to receive liquid containing the unevaporable constituent by spattering as a result of the ebullition of the evaporable constituent of the liquid in the evaporator, and means forming a drain for removing liquid in the receiver from the evaporator, said drain means comprising a conduit havinga series of pockets into which the liquid delivered by the receiver may successively flow to permit the evaporable constituent to be rapidly separated from the unevaporable con=I lstituent by evaporation and the unevaporable the header, extractor means comprising a re-v ceiver element disposed in said header above the liquid level therein and opposite said duct, and

means for delivering an evaporable liquid into said duct at a point removed from said header whereby to produce vigorous ebullition of the liquid immediately beneath the receiver element, a suction connection on said evaporator above the liquid level in said header, and means forming a conduit for draining liquid from the receiver element to said suction connection, said conduit means forming a plurality of pockets through which liquid, drained from the receiver element, successively cascades whereby to permit evaporation of the evaporable constituent of said liquid.

5. An evaporator or boiler comprising sheet metal means forming an evaporator space comprising spaced headers and a plurality of ducts opening at their opposite ends in the headers, said evaporator being adapted to receive an in said headers, extractor means in at least one of said headers comprising a receiver element disposed above the liquid level therein substantially opposite at least one of said ducts, means for delivering liquid into the duct opening in said header opposite said receiver element whereby to produce vigorous ebullition of the liquid ,beneath said receiver element, means interconnecting said headers above the liquid level therein, a suction connection in the other of said headers than that containing the receiver element, and

means comprising a pipe connecting with said suction connection outwardly of said evaporator and extending through the Wall of the header containing the receiver element, said receiver element being arranged to drain into said pipe to deliver liquid from the receiver into said conduit and thence into the suction connection.

6. An evaporator as set forth in claim 5, wherein the pipe, outwardly of the evaporator, forms a series of pockets through which the liquid, drained from the receiver element, successively cascades whereby to permit evaporation of the evaporable constituent of said liquid to the end that the non-evaporable constituent of the liquid may be delivered to the suction connection in liquid condition.

7. A ooded evaporator for a refrigerating machine, said evaporator including a header for separating liquid and gaseous refrigerant, a refrigerating circulating conduit communicating with said header, means for admitting refrigerant to said evaporator, and means for withdrawing a mixture of refrigerant and lubricant entrained therein from said header, said means including a series of pockets arranged to permit the evaporation of liquid refrigerant. from the mixture passing through the pockets and to cause the residual liquid to ow progressively from one end of the series of pockets to the other toward the outlet end of the withdrawing means.

MAHLON W. KENNEY. ARTHUR R. CONSTANTINE. 

